365
FXUS63 KAPX 161619
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1119 AM EST MON DEC 16 2024
KEY MESSAGES
- FOG POTENTIAL CONTINUES TODAY WITH POCKETS OF SIGNIFICANTLY
REDUCED VISIBILITY.
- LIGHT RAIN CHANCES MID-MORNING THROUGH THIS AFTERNOON.
- SNOW CHANCES AND COOLER TEMPERATURES RETURN MID WEEK.
UPDATE
ISSUED AT 1119 AM EST MON DEC 16 2024
MORNING SYNOPSIS: OVERCAST SKIES ACROSS NORTHERN MICHIGAN AT MID
MORNING WITH FOG/LOW STRATUS ACROSS EASTERN UPPER AND EAST OF M-37
ACROSS NORTHERN LOWER. BROKEN BAND OF RAIN SHOWERS LIFTING
NORTHEAST ACROSS NORTHERN MICHIGAN AS WELL...THOUGH IR/WATER VAPOR
IMAGERY SHOWS DRIER AIR ALREADY SPREADING ACROSS LAKE MICHIGAN.
SHOWERS BEING DRIVEN BY THE TAIL END OF A SHORT WAVE TROUGH NORTH OF
LAKE SUPERIOR...AIDED NARROW AXIS OF DEEPER MOISTURE AND LOW LEVEL
THETA-E POKING UP INTO SOUTHERN LAKE MICHIGAN/SOUTHWEST LOWER
MICHIGAN. SECOND VORTICITY MAXIMUM SPINNING ACROSS NORTHERN IOWA
WITH SOME SCATTERED RADAR RETURNS. 13Z SURFACE ANALYSIS SHOWS A
1002MB LOW CENTER OVER NORTHWEST ONTARIO...COLD/OCCLUDED FRONT
ARCS SOUTHWARD INTO WESTERN UPPER/EASTERN WISCONSIN/WESTERN
ILLINOIS. WARM FRONT ACROSS SOUTHERN PORTIONS OF
ILLINOIS/INDIANA THOUGH ONE COULD ARGUE OF A SECOND WARM FRONT
FROM SOUTHERN LAKE MICHIGAN/ NORTHERN INDIANA/SOUTHWEST OHIO.
12Z APX SOUNDING SHOWED MOISTURE TRAPPED BENEATH A SUBSIDENCE
INVERSION CENTERED AROUND 900MB... FREEZING LEVEL ABOVE 6800FT
AGL. HIGHER RELATIVE HUMIDITY BELOW 700MB AT GRB BUT SATURATION
STILL CONFINED BELOW 900MB.
FORECAST UPDATE: ONTARIO SURFACE LOW WILL TRACK EAST TODAY REMAINING
WELL NORTH OF LAKE SUPERIOR...COLD/OCCLUDED FRONT WILL CROSS THE
FORECAST AREA THIS AFTERNOON. FRONT SHOULD BE OUT OF NORTHEAST
LOWER AROUND 00Z +/- 1 HOUR. IOWA VORTICITY CENTER WILL MAKE ITS
WAY INTO SOUTHERN LOWER LATE THIS AFTERNOON...MOVING THROUGH THE
THUMB REGION AND INTO LAKE HURON BY MIDNIGHT.
EXPECT THAT WE'LL BE LOOKING AT TWO ROUNDS OF SHOWERS TODAY...THE
CURRENT BATCH EAST OF THE US-131 CORRIDOR WHICH WILL PUSH INTO LAKE
HURON BY MID AFTERNOON (AND PROBABLY TAPERING TO DRIZZLE)...AND THEN
ANOTHER ROUND WITH THE IOWA SHORT WAVE TROUGH THAT SHOULD INCREASE
POPS INTO NORTHWEST LOWER AFTER 21Z. EXPECT FOG TO PERSIST AS WELL
WITH UPPER 30S-LOWER 40S DEW POINTS CROSSING AN AT OR BELOW FREEZING
SURFACE/SNOWPACK.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 231 AM EST MON DEC 16 2024
PATTERN SYNOPSIS/FORECAST: EARLY THIS MORNING, NORTHERN MI IS
SANDWICHED BETWEEN TWO MID-LEVEL WAVES. THE FIRST, NOW DOWNSTREAM,
ASSOCIATED WITH YESTERDAY'S OCCASIONALLY INCLEMENT WEATHER. THE
SECOND STILL UPSTREAM OVER ND/SOUTHERN MANITOBA. ATTENDANT SURFACE
LOW WITH THIS LATTER FEATURE WILL CROSS NORTHERN ONTARIO OVER THE
NEXT 24 HOURS WITH A COLD/OCCLUDED FRONT SWINGING THROUGH THE
FORECAST AREA THIS AFTERNOON. COLD ADVECTION IN THE WAKE OF THIS
BOUNDARY IS EXPECTED FOR TONIGHT INTO TUESDAY WITH RENEWED LAKE
INDUCED RAIN/SNOW SHOWER CHANCES BECOMING THE RULE ACROSS PARTS OF
NORTHERN LOWER AND EASTERN UPPER MICHIGAN.
FORECAST DETAILS: CERTAINLY QUITE GRUNGY OUT THERE AT THIS EARLY
HOUR WITH LOTS OF LOW CLOUDS AND POCKETS OF SIGNIFICANTLY REDUCED
VISIBILITIES IN AREAS OF FOG (ESPECIALLY INLAND). HAVE REISSUED A
SPS THROUGH THE MORNING COMMUTE TIME TO COVER THIS. NOT A TON OF
CHANGE IN THIS EXPECTED TODAY IN ADVANCE OF A COLD FRONT SET TO
CROSS THE AREA FROM WEST TO EAST LATER THIS AFTERNOON. RAIN SHOWER
CHANCES RETURN IN ADVANCE OF THIS BOUNDARY, ESPECIALLY MID-MORNING
THROUGH THIS AFTERNOON. QPF AMOUNTS GENERALLY LESS THAN 0.15" AREA-
WIDE. HIGH TEMPS TODAY RANGE FROM THE UPPER 30S FAR NORTH TO THE MID-
40S NEAR SAGINAW BAY.
PRESSURE GRADIENT INCREASES BEYOND THE FRONTAL PASSAGE AS WINDS VEER
MORE WESTERLY WITH TIME THIS EVENING THROUGH TONIGHT LEADING TO
GUSTS AS HIGH AS 30 MPH OR SO. LOW-MID LEVEL COLD ADVECTION TO BE
THE RULE WITH AN INCREASINGLY SUPPORTIVE OVER-WATER THERMAL GRADIENT
EXPECTED OVER LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN BY 03Z. LAKE
INDUCED RAIN SHOWERS EXPECTED TO INCREASE NEAR WHITEFISH PT AND IN
THE TYPICAL WEST FLOW LAKE BELTS OF NORTHERN LOWER TOWARD MIDNIGHT
AND BEYOND. SOME OF THESE SHOWERS LIKELY TO MIX WITH OR CHANGE OVER
TO WET SNOW OVER THE HIGHER TERRAIN, ESPECIALLY AFTER 08-09Z. SOME
MINOR SNOW ACCUMULATIONS BECOME PROBABLE BY EARLY TUESDAY MORNING --
AGAIN WITH THE HIGHEST PROBABILITIES OF UP TO ~0.5" OVER THE
INTERIOR HIGHER TERRAIN OF BOTH NORTHERN LOWER AND THE EASTERN U.P.
LOW TEMPS TONIGHT FALLING BACK TO THE UPPER 20S TO LOW 30S WITH WIND
CHILLS DIPPING INTO THE UPPER TEENS AND LOW 20S.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
ISSUED AT 231 AM EST MON DEC 16 2024
FORECAST PATTERN:
TUESDAY MORNING, WEST WINDS AND WEAK UPPER LEVEL TROUGHING WILL
ALLOW LIGHT LES SHOWERS TO LINGER NEAR THE TIP OF THE MITT AND
EASTERN UPPER. SKIES WILL BE MOSTLY CLOUDY WITH TEMPERATURES
BEGINNING A GRADUAL COOLING TREND (HOWEVER HIGH TEMPS REMAIN NEAR
FREEZING). EARLY WEDNESDAY, A SURFACE COLD FRONT AND WEAK UPPER
LEVEL TROUGHING WILL APPROACH THE GREAT LAKE REGION. MORE WIDESPREAD
CHANCES FOR SNOW EXISTS, HOWEVER SINCE THE FORCING IS WEAK AND
MOISTURE IS MOSTLY CONTINENTAL - ANY ACCUMULATIONS WILL BE LIMITED
TO A FEW INCHES. SURFACE WINDS BECOME WEST TO NORTH WEST BY
WEDNESDAY AFTERNOON AND WILL REMAIN LIGHT TO BREEZY. TEMPERATURES
WILL START TO RETURN TO NEAR NORMAL FOR THE END OF THE WORK WEEK AS
A CANADIAN AIRMASS GETS CLOSER. A PROGRESSIVE WEAK UPPER WAVE
CONTINUES SNOW CHANCES INTO FRIDAY, BEFORE A COLDER SURFACE HIGH
(1040 MB) SLIPS BY JUST NORTH OF THE GREAT LAKES REGION THIS
WEEKEND. THIS FEATURE WILL LEAD TO COLDER TEMPERATURES RETURNING,
HOWEVER DETERMINISTIC GUIDANCE HAS HAD SOME RUN TO RUN
INCONSISTENCIES.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 614 AM EST MON DEC 16 2024
LOW STRATUS (LIFR TO LOW MVFR) AND FOG ARE EXPECTED TO PERSIST
TODAY, ALONG WITH INCREASING RAIN SHOWER CHANCES IN ADVANCE OF A
COLD FRONT EXPECTED TO CROSS WEST TO EAST THIS AFTERNOON.
INCREASINGLY GUSTY WEST WINDS ANTICIPATED THIS EVENING THROUGH
TONIGHT WITH CIGS SLOWLY IMPROVING TO MVFR LAKE INDUCED STRATO-
CU.
APX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 PM EST
TUESDAY FOR LHZ345>347.
SMALL CRAFT ADVISORY UNTIL 4 PM EST TUESDAY FOR LHZ348-349.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM EST
TUESDAY FOR LMZ323-341-342-344>346.
SMALL CRAFT ADVISORY UNTIL 4 PM EST TUESDAY FOR LSZ321.
UPDATE...JPB
SHORT TERM...MJG
LONG TERM...ELD
AVIATION...MJG
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page